Chp. 11-13 Exam Review Flashcards
What do you get when you oxidize secondary alcohol with PCC?
Ketone
What is Markovnikov’s Rule?
* “The rich get richer”
* The carbon with the largest # of carbon atoms gets the X (halogen) or OH bind to it
What is conjugation?
Sequence of alternating double or triple bonds.
What are 5 common nucleophiles?
I-
Br-
Cl-
HS-
H2S
RSH
HO-
RO-
NC-
What happens when secondary alcohol undergoes… a) KMnO4 b) H2CrO4 c) PCC
The secondary alcohol is converted to… a) Ketone b) Ketone c) Ketone
What is oxidation?
- Loss of electrons; 2. Adding an oxygen; 3. Adding an additional bond to the oxygen (eg. from single bonded oxygen, it becomes double bonded)
What are the names of the molecules from left to right?
Ketone; aldehyde; carbocyclic acid
What reagent can you use to convert an alkene to an epoxide?
MCPBA
What is chromic acid?
H2CrO4
What reagents can you use to reduce a ketone to a 2* alcohol?
NaBH4 or LAH
What product do you get when you apply PCC on a 1* alcohol?
Aldehyde
Are the following acids strong or weak? What are their pkas?
I-H
Br-H
Cl-H
SO3-H
HO3+
These are strong acids. Their pkas are…
I-H -11
Br-H -9
Cl-H -7
SO3-H -3
HO3+ -2
What product do you get?
What is this molecule?
Benzene
What do you get when you oxidize a 1* alcohol with H2CrO4?
Carboxylic Acid
What does aprotic mean?
The solvent does NOT have a proton on an electronegative atom.
Are the following acids strong or weak? What are their pkas?
H20
1* alcohol
3* alcohol
NH3
These are weak acids. Their pkas are…
H20 15.7
1* alcohol 16
3* alcohol 18
NH3 38
If the top row is a reactant, and the bottom row is the product, is this oxidation or reduction? Why?
Reduction. You are adding an H. (Gained electrons)
What is the product if you use KMnO4, H2CrO4 or PCC with tertiary alcohol?
No Reaction
What do you get when you oxidize primary alcohol with KMnO4?
Carboxylic Acid
What product do you get if you reduce a carboxylic acid with NaBH4?
No Reaction
What happens when primary alcohol undergoes… a) KMnO4 b) H2CrO4 c) PCC
The primary alcohol is converted to… a) Carboxylic acid b) Carboxylic acid c) Aldehyde
Examples of polar aprotic solvents.
acetone, DMSO, DME and DMF
When primary alcohol undergoes PCC, what happens?
It becomes an aldehyde.
What are examples of reducing agents?
1) LiAlH4 (LAH);
2) NaBH4, H20;
3) H2, Ni;
4) Na, EtOH
Is this oxidation or reduction?
What are the reagents to get the products from top to bottom?
This is oxidation.
KMnO4
H2CrO4
PCC
What is a reduction?
Gain of electrons.
What three reagents can you use to convert a 2* alcohol to a ketone?
KMnO4 and H2CrO4 and PCC
Does strong Acid have a weak conjugate base?
True
What happens when tertiary alcohol undergoes… a) KMnO4 b) H2CrO4 c) PCC
What happens when tertiary alcohol undergoes… a) No reaction b) No reaction c) No reaction
What do you get when you reduce a carboxylic acid with LAH? How about with NaBH4?
1* alcohol; No Reaction
What is the product from top to bottom?
What mechanism is this? You have a tertiary, nucleophile, leaving group and a polar solven to stabilize the carbocation.
SN1
This mechanism works for primary, maybe secondary; you need a strong nucleophile and leaving group; there is an inversion at the chirality center, need a polar solvent to dissolve nucleophile and it is favored by polar aprotic solvents.
SN2
What is Hoffman Rule
* Elimination yields the least substituted alkene
* use a bulky base such as tert-butoxide (t-BuOK) in tert-butyl alcohol (t-buOH).
* Favors substrates that can form stable carbocations.
* Bulky group
*Alcohols dehydrated follows this mechanism in 2* and 3* alcohols
* Favored by use of POOR NUCLEOPHILES (weak bases)
E1
* Uses a 2* or 3* alkyl halide is possible;
* HIgh temperature favors elimination over substitution
* Use EtONA/EtOH and t-BuOK/t-BuOH
Zaitsev product
* Primary alcohols follow this mechanism or rearrangement
* H must be anti to leaving group
E2
